Researchers [in Israel] looked at 1,112 rulings involving requests for parole (or for changes of incarceration terms) presented to eight judges. They heard cases daily, interrupting for a morning snack and lunch.
The odds of an inmate receiving a favorable decision started at 65%, first thing in the morning, then steadily dropped until the snack break. If the judge heard eight cases in the morning, the average success rate for the last one was 25%. If the judge heard 12 cases, the average success rate for the final one was 0%. Favorable rulings popped back up to 65% when the judge returned, then slid again until lunchtime. The same pattern appeared post-lunch.
The authors could find no other factors that might explain the pattern beyond the hearing’s timing, relative to the food breaks. They had no direct measure of the judges’ mood.